This SO Answer provides a method of setting this level globally, throughout your app.

Additionally, if you use a [DDLog addLogger:someLogger withLevel:DDLogLevelVerbose]; without setting the global ddLogLevel, you won't get you logs outputted. So your best bet is to always set ddLogLevel to LOG_LEVEL_VERBOSE (or DDLogLevelVerbose in the newer versions of CocoaLumberjack) and then reducing the log level on the individual loggers.